Often used in compound nouns such as 書き損じ (writing error) or 聞き損じ (mishearing). As a standalone noun, it refers to a mistake or failure, but it is more common in compounds.
I threw away the letter with a writing mistake.
That was my mishearing.
harm; hurt; injure; damage
blunder; failure; mistake; error
mistake; error; blunder; failure
The noun form of the verb 損じる (to damage, to spoil). The kanji 損 means 'loss' or 'damage'.